I think it is a recipe issue. You clearly followed it precisely. But, I suspect it has a couple of flaws. First, the recipe doesn't contain enough egg protein to set that amount of liquid. Second, the recipe is extremely high in fat, which combined with the lack of sufficient egg protein, also contributed to the broken appearance. I've never made pots de crème with butter. I understand that it was included to give the butterscotch effect, but there is a more reliable way.

Measure 1/2 cup of granulated (not brown) sugar. Warm a saucepan over medium heat. Add a tablespoon of sugar to the center of the pot. When it has melted, add another tablespoon and allow it to melt also. Proceed this way until all of the sugar has been melted and reaches a deep golden brown color. Then add 8 ounces of whole milk and 8 ounces of cream (pour the milk in carefully - remember, the pan is really hot); whisk to blend with the caramel, and bring the mixture to a boil.

In a mixing bowl, whisk together 2 egg yolks and 2 whole eggs. In a steady stream, whisk in 1/4 cup of granulated sugar. Temper in the hot mixture. Add 2 teaspoons of vanilla extract. The protein in the egg whites (ovalbumin) will lend enough structure to allow your custards to set, while still being beautifully spoonable because of the tenderizing effect of lipids (fats) in the yolks and the cream, which is less than half the volume in your recipe.

Set a sieve over a large measuring cup (it's easiest to pour from), and strain the custard into the cup. Fill your ramekins 3/4 full. Bake them in a water bath at 325 degrees for about 30 minutes. I set an inverted baking sheet over the tops of the ramekins - it's easier to remove and check for doneness than foil.

The custards are done when you can gently bump the edge of a ramekin (cover your fingertips with a kitchen towel), and the custard will "jiggle like jello, not wiggle like a wave." That is a direct quote from one of my favorite chefs in culinary school, and it has never failed me.

Thanks so much. I enjoy learning the 'why' of things and you've explained that well. I'll try your recipe next. I also love the tip about the inverted baking sheet over the top ... so much easier than lifting foil to test a jiggle! Is there a source where I can learn more about what is considered standard ratios for fat to eggs?

What a wonderful question, akm. First of all, the classic definition of a custard is that which is set by coagulation of egg protein. By that definition, cheesecake is a custard. So is pumpkin pie. Lemon curd. I have a feeling that you're interested in individual, baked custards. So, at the top of their egginess scale is flan, or crème caramel. It's a stand-alone custard, turned out of its ramekin onto a plate, where it holds its shape. It can do so because it is much higher in whole eggs: only 25% yolks to whole eggs. Too, it is traditionally made with whole milk only and no cream, so there are fewer fats to tenderize the ovalbumin in the egg whites.

Next on the scale are your pots de crème with a ratio of 1:1 yolks to whole eggs. Last is crème brûlée, which is made with cream only and a ratio of 6:1 yolks to whole eggs.

P.S. While pots de crème cannot be turned out of their ramekins and still hold a shape as crème caramel can, once chilled, I've successfully scooped the custard with a small ice cream scoop and it mounds very nicely. Crème brûlée? Not a chance.

I do love this info. It's so hard to look at a recipe on the internet and have ANY idea if it's close to something that will work or if it's someone who's altered something to the point where it's not likely to really work. (Someday if I have the time I'd love to take some baking classes at a culinary school --- because I really want to see the differences in over kneading, under kneading, over proofing, under proofing and have someone who knows what they're talking about talk about texture and crumb structure .... someday) Thanks for you expertise.